Sudan's President Omar Hassan al-Bashir and southern counterpart Salva Kiir met on Saturday in Khartoum on the latter's first visit since South Sudan seceded in July from its former civil war foe.
Diplomats hoped Kiir's two-day visit would ease tensions that have grown since the split and end a stalemate in talks.
The two countries have failed to agree how to share oil revenues and other assets, divide up debt, calm the joint border area and agree what to do about the disputed region of Abyei.
"We confirm the principle not to go back to war but to be good neighbours and leave the bitterness of the past behind," Bashir said at a reception open to the media.
Khartoum wants to develop trade relations and will keep its Red Sea port of Port Sudan and Nile river access open for exports from the landlocked south, he said, citing agriculture as example of cross-border cooperation. Kiir said the era of war had ended with the 2005 peace deal.
"We are committed as you are committed not to go back to war," he said in a speech. "We are committed to find solutions."
Both countries set up five committees to strengthen ties, especially on trade cooperation, according to the Sudanese Media Centre (SMC), a news website linked to the northern government.
North and south also want to discuss Sudan's external debt, northern finance minister Ali Mahmood told SMC. Juba has refused to take $38 billion debt incurred when the country was united.
The two sides reached an agreement last month to facilitate travel and trade after much of the joint border was closed in the run-up to southern independence.
But talks over how to share oil revenues, the lifeline for both economies, have been stalled for months. South Sudan took most of the country's oil production but needs northern export facilities and Red Sea access.
Juba will need to pay a transit fee but has not paid anything since July, in the absence of an agreement, diplomats say. Both countries have been hit hard by an economic crisis with inflation spiralling.
The African Union and former South African President Thabo Mbeki have tried to mediate but little has been resolved.
Khartoum has accused Juba of supporting armed opposition groups fighting the army in northern border states of South Kordofan and Blue Nile, a charge South Sudan denies.